Figure 6.

spi1-25 cells show mitotic spindle defects. Early mitotic spindle defects in an asynchronous culture of the spi1-25 mutant held at 36°C for 3 h when most aberrant phenotypes were scored. Each panel shows four different images of the same cell: the first DIC with DAPI staining (a, e, and i) shows the cell outline and position of the chromatin; the second shows chromatin staining by DAPI (b, f, and j); the third and fourth show immunofluorescence of tubulin (c, g, and k) and the spindle component Sad1p (d, h, and l), respectively. The two predominant spindle defects are shown: star-shaped monopolar spindles and condensed chromatin (c and b, bottom cell; g and f) and a tiny premetaphase spindle (c, top cell; k) between duplicated and separated spindle pole bodies (d, top cell; l) and not visibly condensed chromatin (b, top cell; j). Tubulin staining of the nucleus in k shows nuclear import of tubulin. Bars, 10 μm.